The present invention relates to an artificial vessel having an excellent patency. More particularly, the present invention relates to an artificial vessel having an excellent patency, wherein the vessel wall is made of an elastomer having a porous structure and the contact surface with blood has pores with a mean diameter of from 1 to 100 .mu.m and holes with a mean diameter of from 0.01 to 10 .mu.m.
In recent years, study on the artificial vessel has proceeded with progress in vascular surgery and many artificial vessels have been developed. Hitherto, for an artificial artery of a medium- or large-caliber with a diameter of about not less than 6 mm, the Debakey artificial vessel made of woven Dacron (USCI. Co., Ltd. of U.S.A.), the Gore-Tex vessel (Gore Co., Ltd. of U.S.A.) which is made of an expanded polytetrafluoroethylene (hereinafter referred to as "EPTFE"), and the like have been clinically used.
The above artificial vessels have pores which communicate the inside and the outside of the vessel wall. Soon after the artificial vessel is grafted into a living body, it is encapsulated to serve as the artificial vessel. Such property of having the communicating pores suited for encapsulation is hereinafter referred to as "porosity".
However, these artificial vessels have a disadvantage in that they have poor patency and thus cannot be clinically used as artificial veins or as artificial arteries of a small-caliber with an inner diameter of not more than about 6 mm. Therefore, a patient's own veins have hitherto been used in vascular reconstructive surgery of arteries below the knees or of the coronary arteries-aorta bypass.
In order to reduce the above disadvantage of an conventional artificial vessel and to obtain the artificial vessel having an excellent patency, it appears to be important for the artificial vessel to have a compliance approximate to that of a vital vessel and to have a contact surface with blood suited for encapsulation as well as to have a porosity suited for encapsulation.
The present inventor has already found that an artificial vessel wherein the vessel wall is made of an elastomer having a porous structure has a compliance approximate to that of a vital vessel, a porosity and a contact surface with blood both suited for encapsulation and an excellent patency, and have filed patent applications therefor (Japanese Patent Application No. 39077/1984, No. 39971/1984, No. 39972/1984, No. 44396/1984, No. 44397/1984, No. 44398/1984, No. 51768/1984, No. 52674/1984 and No. 99131/1984).